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Old 2nd July 2007, 10:13 PM   #1
taj is offline taj
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Default Bryston to Quasi

I decided to separate my ramblings from Con's main Brother of Quasi (NBIP) thread since it's more about my custom retro-fit project than his circuit, and I don't want to pollute his main thread anymore than I already have.

So, to recap, I'm retrofitting a Bryston 4B chassis with the Quasi NBIP (N-channel bipolar) Quasi Complimentary amp circuit. But Cons' original PCB layout won't fit into the chassis so I am altering his board to fit. The chassis also uses 4 heatsinks per side that hold 2 TO-3 transistors each. The 4th heatsink is 'around the corner' on the chassis so to speak.

So this PCB layout is my mod to make it fit into the chassis and work with the existing TO-3 heatsinks. NB: The PDF file uses layers so if you have a recent version of the Adobe reader, you can turn them on-off to view the traces, the parts or the output transistors behind -- if you can figure out how. Hint: nav. panel.

The output transistors connect with wires that feed through holes in the PCB that are located as near as I could get to the transistors, except the 4th pair which doesn't require a hole.

Any concerns/mistakes here? Assume I got the circuit correct (I don't expect anyone to trace it for accuracy) and I'll take responsibility for making that so. I'm thinking more about heatsinking, thermal coupling, instability due to layout problems. That sort of thing.

The drivers now mount on their own small heatsink similar to the pre-drivers. Is it big enough?

Thanks.

..Todd
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Old 2nd July 2007, 10:20 PM   #2
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Hey Todd,
Why did you pick an amp with such an ugly face and terrible reputation for sound do upgrade??? Mind you, it will be a massive upgrade.

Ahhhh, just figured it out. You're building a "sleeper", except it's not a car.

I don't know about the board, but it's a marvelous idea. Keep us informed please.

-Chris
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Old 2nd July 2007, 10:33 PM   #3
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Quote:
Originally posted by anatech
Hey Todd,
Why did you pick an amp with such an ugly face and terrible reputation for sound do upgrade??? Mind you, it will be a massive upgrade.

Ahhhh, just figured it out. You're building a "sleeper", except it's not a car.

I don't know about the board, but it's a marvelous idea. Keep us informed please.

-Chris

Hi Chris.

There's nothing about the faceplate that a wire-wheel and a can of spray paint can't fix.

And for the sound? Well why do think it's getting the Quasi circuit?

The hardware is great. Far too valuable to use to keep my car from rolling back down the driveway. (which is plan B)

..Todd
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Old 2nd July 2007, 10:46 PM   #4
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Hi Todd,
As a joke, you should leave the faceplate be. Use a "MKII" sticker or something. "by Quasi" would be nice on a lower corner.

Quote:
The hardware is great. Far too valuable to use to keep my car from rolling back down the driveway. (which is plan B)
I did see a 4B used for that a few years ago. I thought it was both understandable and hilarious at the same time.

I'm thinking of a 4B retrofit kit.

-Chris
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Old 2nd July 2007, 11:19 PM   #5
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Quote:
Originally posted by anatech
Hi Todd,
As a joke, you should leave the faceplate be. Use a "MKII" sticker or something. "by Quasi" would be nice on a lower corner.
-Chris
How about this:
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File Type: gif qryston.gif (4.5 KB, 894 views)
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Old 2nd July 2007, 11:32 PM   #6
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Quote:
Originally posted by anatech

I'm thinking of a 4B retrofit kit.
-Chris

Are you serious about that? Help me turn the Quasi NBIP amp into a 4B retrofit kit, if you're game. I'll do all the drawing, I just need the technical direction. It'll help me with my learning too.

..Todd
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Old 2nd July 2007, 11:48 PM   #7
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Heck, why not go all the way....
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Old 3rd July 2007, 12:50 AM   #8
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Hi Todd,
I hope Quasi doesn't feel insulted by the association with Bryston.

Once you have the buggies worked out, see if there is interest in a GB. I don't think it will be that popular but it doesn't cost anything to find out.

-Chris
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Old 3rd July 2007, 01:20 AM   #9
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Quote:
Originally posted by anatech
Hi Todd,
I hope Quasi doesn't feel insulted by the association with Bryston.

Once you have the buggies worked out, see if there is interest in a GB. I don't think it will be that popular but it doesn't cost anything to find out.

-Chris

Well, as long as we're replacing Bryston circuitry with Quasi circuitry, Con should feel rightly proud. However, I would NEVER have a faceplate that insinuated the Quasi amp had any relationship to the Bryston products. Just wouldn't be kosher.

(And FWIW, of all the amps I have, the Bryston 4B's are NOT the worst sounding!) but there's plenty of room for improvement.

I guarantee there won't be interest in group buy to retrofit 4B's. The beauty of Quasi is that it's a single-sided PCB, same voltage range, same output device format, so as a DIY Bryston retrofit project, it's almost a no-brainer. So, if it works out, I'll keep the information on the web for anyone else willing to tackle it.

..Todd
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Old 3rd July 2007, 01:39 AM   #10
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Hi Todd,
You may be surprised by the number of takers on this. There are a ton of "dead soldiers" around.

-Chris
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